Embodiments of the present invention generally relate to apparatus and methods for facilitating donning and doffing of a prosthesis and improving the retention and fit thereof. More specifically, the present invention relates to apparatus and methods for facilitating donning and doffing of a prosthesis and improving the retention and fit thereof via inclusion of a prosthetic valve having a slideable, maintained release mechanism.
Various prosthetic devices for limb replacement are known in the art. Many such prosthetic devices include a socket that serves as the connection between the user (i.e., the amputee) and the prosthesis. For load bearing prostheses (e.g., lower limb prostheses such as above the knee prostheses), the weight of the amputee is transferred to the ground via the socket.
For most users, a socket-type prosthesis is suspended by a negative pressure or vacuum created by the distal motion of the prosthetic socket relative to the residual limb. In order to don (i.e., put on) the prosthetic device, the user pulls the prosthesis over the residual limb until the residual limb is fully inserted into the socket. The socket is typically reduced to provide some compression on the limb. This compression creates a seal between the residual limb and the interior wall of the prosthetic socket such that any distal motion of the prosthetic socket relative to the residual limb will create a slight vacuum that retains the prosthesis (e.g., during the swing phase of walking). The successful fitting of a prosthetic socket results in the effective transfer of forces from the residual limb to the prosthetic socket such that the amputee can maintain daily activities without tissue damage or pain.
Socket-type prostheses known in the art typically include a port extending from the prosthetic socket to the environment external to the socket. During use of the prosthesis, some such ports are closed to the environment via a plug or a valve such that a vacuum is maintained within the prosthetic socket. Some such valves include adjustable or non-adjustable leak rates to bleed air introduced into the prosthetic socket. Other known valves include a pressure relief mechanism. These valves (e.g., one way check valves) are typically set to a predetermined setpoint (e.g., ½ PSI) to allow the valves to completely displace any air that enters into the prosthetic socket when a load is applied to the residual limb (e.g., when the user places pressure on the prosthesis during a step). This displacement ensures a comfortable and reliable fit of the prosthesis.
When a user wishes to remove a prosthesis, it is necessary to relieve the vacuum, or near vacuum, created within the prosthetic socket. In some known embodiments, this vacuum relief is accomplished via removal of the plug installed in the prosthetic socket port. This may be a cumbersome task as many such plugs must be unscrewed. In other known embodiments, this vacuum relief is accomplished via actuating the valve located in the prosthetic socket port to relieve the vacuum. A variety of actuation apparatus and methods are known. Some such valves require the user to maintain a button in a depressed position until the residual limb is fully removed from the socket. This type of removal may also be difficult for a user.